I do not know if this could cause the problem or not but it is hooked up to an extension cord (not sure what size). There are two garage doors plugged in with extension cords. One is working but it is closer to the outlet. Could this be the cause of the problem? Either way I am going to install outlets so she can plug them in correctly.

  • 2
    Check the optical sensors, then check the balance of the door by disconnecting the opener and opening the door halfway by hand.
    – isherwood
    Commented Apr 16, 2020 at 13:06
  • Similar, not same, but answer applies the same - check manual for procedure, test, contemplate replacement as well as repair. Unless it's wildly inadequate I doubt the extension cord has anything to do with the problem. diy.stackexchange.com/a/149176/18078
    – Ecnerwal
    Commented Apr 16, 2020 at 13:10
  • Disconnect the opener and operate the door fully through several cycles by hand. It should roll easily. If not, fixing it is job 1. Broken garage doors can kill you, especially when forced. Commented Apr 16, 2020 at 16:19
  • Need more info: does the door start up & stop almost immediately, or does it close, say halfway before stopping? Does it not start at all unless you hold down the button? If the latter, my bet is on a bad "hold" relay in the main motor box. Commented Apr 16, 2020 at 20:10
  • As suggested below, a door will generally refuse to close if the optical sensor at the bottom of the door opening detects an obstruction. But this behavior can be overridden by holding the wired opener control button in until the door is all the way down.
    – Hot Licks
    Commented Apr 17, 2020 at 1:58

4 Answers 4


99% of the time, the issue is the door sensor. Usually an infrared beam, it runs across the bottom of the doorway to reverse the door if anything blocks it. You'll need to check them. There's typically a green light unit (transmitter) and a red light unit (receiver). The red light will flash if there's no beam from the transmitter.

  1. Make sure they are aligned properly. If someone bumped it, it can fail easily
  2. Make sure the sun is not hitting the transmitter or receiver. In the spring and fall, it sometimes hits mine and causes issues at certain times of the day.
  3. Make sure nothing is covering any holes. My newer Genie unit has transmitters that have a nice hole for spiders to build a nest in. A can of compressed air can help with that
  • I agree+ the receiver on or off depends on the model if in light mode or dark mode most are on with light the light beam made.
    – Ed Beal
    Commented Apr 16, 2020 at 14:09
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    Really? I haven't seen an opener system where holding down the button can override the safety switches. Commented Apr 16, 2020 at 20:08
  • @CarlWitthoft If you physically hold the button, the opener will move, even if the safety system wouldn't allow it. Otherwise you have people unhooking the door and moving it manually, which might be even more unsafe.
    – Machavity
    Commented Apr 16, 2020 at 20:44
  • @CarlWitthoft Several houses ago, I had an older system that did this. The beam could be overridden, but the door would still reverse on unexpected contact. I do not recall the make and model, but I think it might have been Craftsman. Commented Apr 17, 2020 at 13:32

Running the extension cords is not causing the problem but you're smart to install the outlets and correct the installation.

The momentary operation of the wall switch triggers a normally open relay to close in the unit that operates the motor until the limit switches open the circuit. Check that relay.

  • Yeah, I'm going with the relay too. Commented Apr 16, 2020 at 20:11

Often the door opener, by not working, is working exactly how it is supposed to work because it's not supposed to work when there is a safety issue such as someone (a child) standing under the door.

If nothing is in the way of the door then the door opener is getting faulty information. The 'not supposed to work' signal comes from a safety sensor near the bottom of the door and near or on the metal door track.

It works by transmitting a type of light (we usually can't see it) across the door gap and seeing the reflection if it off of a reflector on the other side. If something blocks the light then it assumes that something is in the way, that the path is not clear.

For the door opener to get an 'ok the path is clear' the signal must be complete all the way around, from the door opener down a wire to the transmitter, across the door way, to the reflector, reflected back across the door way returning to the transmitter (also a receiver) and back up the wire to the door opener.

If any part of that path is incomplete then the door opener will not work. Usually it is simply a misalignment of the transmitter, it can't see the return signal not because something (or someone) is physically blocking it by being in the door way, but rather because it is not hitting the reflector and bouncing back. Less often the transmitter/ receiver is dirty, or broken, and sometimes the wire is cut or broken, or it is not attached properly.


If it has an led bulb remove the bulb and see if it will close with the remote. Some led bulbs interfere with some remotes. If this solves the problem then use an incandescent bulb.

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    If they're having to hold the wall button, that implies that merely pressing the wall button doesn't work either
    – Machavity
    Commented Apr 16, 2020 at 13:16

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